XML 62 R50.htm IDEA: XBRL DOCUMENT v3.21.1

Long-Term Debt (Narrative) (Details) - USD ($)		3 Months Ended
	Jul. 01, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 13, 2019	Aug. 31, 2019	Apr. 25, 2017
Debt Instrument [Line Items]
Leverage ratio		2.41
Minimum
Debt Instrument [Line Items]
Leverage ratio		3.0
Maximum
Debt Instrument [Line Items]
Leverage ratio		5.0
Temporary increase to leverage ratio		5.5
Secured net leverage ratio financial maintenance covenants		3.75
Temporary increase to secured net leverage ratio financial maintenance covenants		4.25
Restricted cash payment threshold as amount of availability		$ 100,000,000
Restricted payment threshold as amount of availability		$ 105,000,000
Restricted payment threshold as amount of availability (percent)		4.50%
Federal Funds Rate
Debt Instrument [Line Items]
Spread over variable rate (percent)		0.50%
LIBOR
Debt Instrument [Line Items]
Spread over variable rate (percent)		1.00%
Secured Debt
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity					$ 350,000,000
Secured Debt | LIBOR | Minimum
Debt Instrument [Line Items]
Spread over variable rate (percent)		1.75%
Secured Debt | LIBOR | Maximum
Debt Instrument [Line Items]
Spread over variable rate (percent)		2.25%
Secured Debt | Alternate Base Rate | Minimum
Debt Instrument [Line Items]
Spread over variable rate (percent)		0.75%
Secured Debt | Alternate Base Rate | Maximum
Debt Instrument [Line Items]
Spread over variable rate (percent)		1.25%
Term facility
Debt Instrument [Line Items]
Asset-based loan facility, portion included in current maturities			$ 400,000,000
Term facility | LIBOR
Debt Instrument [Line Items]
Spread over variable rate (percent)		1.75%
Term facility | LIBOR | Forecast [Member]
Debt Instrument [Line Items]
Spread over variable rate (percent)	1.00%
Term facility | Alternate Base Rate
Debt Instrument [Line Items]
Spread over variable rate (percent)		1.75%
5.625% Senior Notes Due 2027 | Senior Notes
Debt Instrument [Line Items]
Senior notes, principal amount						$ 300,000,000
Interest rate		5.625%				5.625%
4.75% senior notes due 2029 | Senior Notes
Debt Instrument [Line Items]
Senior notes, principal amount				$ 500,000,000
Interest rate				4.75%
Senior Notes Due 2023 | Senior Notes
Debt Instrument [Line Items]
Senior notes, principal amount				$ 500,000,000
3.75% Senior Notes Due 2031 | Senior Notes
Debt Instrument [Line Items]
Senior notes, principal amount				$ 500,000,000
Interest rate		3.75%		3.75%

X

- Definition

Debt Instrument, Covenant Compliance, Financial Maintenance Covenants, Secured Leverage Ratio

+ References

No definition available.

+ Details

Name:	musa_DebtInstrumentCovenantComplianceFinancialMaintenanceCovenantsSecuredLeverageRatio
Namespace Prefix:	musa_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Debt Instrument, Covenant Compliance, Financial Maintenance Covenants, Secured Leverage Ratio, Temporary Increase

+ References

No definition available.

+ Details

Name:	musa_DebtInstrumentCovenantComplianceFinancialMaintenanceCovenantsSecuredLeverageRatioTemporaryIncrease
Namespace Prefix:	musa_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Debt Instrument, Covenant Compliance, Fixed Charge Coverage Ratio

+ References

No definition available.

+ Details

Name:	musa_DebtInstrumentCovenantComplianceFixedChargeCoverageRatio
Namespace Prefix:	musa_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Debt Instrument, Covenant Compliance, Fixed Charge Coverage Ratio, Temporary Increase

+ References

No definition available.

+ Details

Name:	musa_DebtInstrumentCovenantComplianceFixedChargeCoverageRatioTemporaryIncrease
Namespace Prefix:	musa_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Line Of Credit Facility, Restricted Cash Payment Threshold As Amount Of Availability

+ References

No definition available.

+ Details

Name:	musa_LineOfCreditFacilityRestrictedCashPaymentThresholdAsAmountOfAvailability
Namespace Prefix:	musa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Line Of Credit Facility, Restricted Payment Threshold As Amount Of Availability

+ References

No definition available.

+ Details

Name:	musa_LineOfCreditFacilityRestrictedPaymentThresholdAsAmountOfAvailability
Namespace Prefix:	musa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Line Of Credit Facility, Restricted Payment Threshold As Percentage Of Availability

+ References

No definition available.

+ Details

Name:	musa_LineOfCreditFacilityRestrictedPaymentThresholdAsPercentageOfAvailability
Namespace Prefix:	musa_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Carrying value as of the balance sheet date of the portion of long-term, collateralized debt obligations due within one year or the operating cycle, if longer. Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16)(a)(1))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_SecuredDebtCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_VariableRateAxis=musa_FederalFundsRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_SecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_BaseRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_CreditFacilityAxis=musa_TermFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_StatementScenarioAxis=srt_ScenarioForecastMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=musa_SeniorNotes5.625PercentDue2027Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=musa_SeniorNotes4.75Due2029Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=musa_SeniorNotesDue2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=musa_SeniorNotes375PercentDue2031Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: